I really don't think Carol is going to be out of the picture for long. I would say that Darryl might go looking for her after Rick finally tells him, but they might have their hands a bit full based on the ending of the last episode.

Either way, I think Rick might be a bit worried about Darryl's reaction to the news, which is why he put off telling him.

I think Rick knew that Carol's life was going to be in danger once Tyrese found out what she did and that played a big part in why he "banished" her.